Re: 300bps Packet (and EHAS) - what is pam, psk, and newpsk,
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Hello Take,It's interesting you bring up the newQPSK setting. I've never found any comprehensive documentation on soundmodem and what some of these other modes are. Do you know? Anybody else on the list know or could comment?
fsk - I know what FSK is but what does it mean in respect to soundmodem? My Yaesu FT-950 supports an FSK input and my US Interfaces Navigator device does FSK too but how would soundmodem use it? Seems it's slowest speed is 4800Bits/sec.
pam - what is pam?psk - I know what PSK is and I use the BPSK31 mode in Fldigi but what would soundmodem do with it in respect to a packet mode?
newqpsk - I know what QPSK is and I've used the QPSK31 mode in Fldigi (has forms of FEC enabled on it) but what would soundmodem do with it in respect to a packet mode? Seems it's slowest speed is 1000Bits/sec.
I would love to learn what these modes do, are they stable, and maybe these modes could be used as a strong alternative to trying/failing 300BAUD HF packet.
900/1100 offset seems to a typical practice for the soundmodem 300bps operation. I share your concern concerning it would not be the practical capability to be used at HF. By the way, does anybody know the implementation status in the radio amateur world about EHAS (Hispano-American Health Link) protocol which is originally based on radio amateur Linux AX.25 and the soundmodem of both FSK and newQPSK modes but adds the several performance improvement techniques likeFEC, Turbocodes, ARQ e.t.c.?The several literatures can be googled by “EHAS”. Regards, take De JA5AEA ________________________________________From: David Ranch [mailto:linux-hams@xxxxxxxxxxx] Sent: Friday, November 26, 2010 4:06 AMTo: Tsutsumi Family; linux-hams@xxxxxxxxxxxxxxx Cc: 'Dave Platt' Subject: Re: 300bps Packet I've used the same 900/1100 offset setting for 300baud HF packet with Soundmodem and things worked OK I suppose. I ultimately came to the conclusion (as did others in my research) that without a beam and high power, HF packet doesn't work very well. I would get four times moreretries than actual good packet exchanges from Santa Clara, CA to say Denver, CO. (Google 'Network 105'). For this exact reason, I've beentracking the Winmor efforts and it's upcoming kb-to-kb mode. I hope one day we'll see it on Linux where we can get a packet-like mode with real FEC for an inexpensive price. I now can now truly appreciate Pactor2/3 but the beyond acceptable high costs of the single vendor TNC and the proprietary nature of the mode are show stoppers for me. Anyway, I have my Soundmodem HF and VHF settings here: http://www.trinityos.com/HAM/CentosDigitalModes/etc/ax25/ If anyone would like to put together a sched. (might be fun to try), emailme.--DavidTsutsumi Family wrote: Dave,Thank you for your quick reply. Along with Phill's configuration parameters i.e. f0=900Hz and f1=1,100Hz in the separate correspondence, the conclusion seems to be that f0 and f1 must be any arbitrary numbers below 1,200Hz and above the low cut frequency of his/her TX/RX audio path with 200Hz gap. As the above conclusion is unique nature of the soundmodem, the fact should be widespread to the new 300bps AFSK SSB users of the soundmodem and I hope Andrew's pointed sites will kindly cover this. Regards, take de JA5AEA -----Original Message----- From: linux-hams-owner@xxxxxxxxxxxxxxx [mailto:linux-hams-owner@xxxxxxxxxxxxxxx] On Behalf Of Dave Platt Sent: Thursday, November 25, 2010 3:37 AM To: linux-hams@xxxxxxxxxxxxxxx Subject: Re: 300bps Packet Tsutsumi Family wrote:Dave,Thank you for providing the tutorial of SM source codes. As one of ways to solve 300bps SSB operation without any code change, you are suggesting to use the frequency setting of f0 and f1 to less than 4 x 300bps =1,200 Hz such as 800Hz and 1,000Hz, not conventional 2,100Hz and 2,300Hz. Correct?Correct - I think this ought to work. As long as you don't pick frequencies so low that your audio connection (PC to rig) is rolling off the amplitude (due to e.g. transformer isolation in the audio path) this approach should let you generate a pair of tones with a suitable separation. You'll just need to tune your sideband rig a bit differently than if you were using a traditional "hard" TNC with its receive filters tuned for a 2200 Hz channel center. Just tune to match up the tone you hear during reception, with the tone that your PC generates during transmission... it'll be an octave or so lower than the usual pitch but it should work. -- To unsubscribe from this list: send the line "unsubscribe linux-hams" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-hams" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html-- To unsubscribe from this list: send the line "unsubscribe linux-hams" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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